Microwave-Assisted Efficient and Green Synthesis of Dihydropyrimidinone(thione) Derivatives via Biginelli Reaction Using Cashew Shell Extract as Natural Acid Catalyst

Cashew shell extract has been found to be a natural acid catalyst, leading to the development of a straightforward, easy, and environmentally friendly Biginelli synthesis of dihydropyrimidinone/thione derivatives. The Biginelli reaction was conducted in a single step under microwave irradiation and provided outstanding yields in a shorter reaction time. The proposed method may be utilized to create dihydro­pyrimidinone/thione derivatives on a wide scale due to simple reaction conditions and low cost and availability of the catalyst.